A method for preparing a rare earth chloride liquid impurity removal agent and simultaneously removing non-rare earth anions and cations

Abstract

The present invention belongs to the technical field of hydrometallurgy, and discloses a method for preparing an impurity removal agent for rare earth chloride feed liquid and simultaneously removing non-rare earth anions and cations. The method comprises: testing and analyzing the rare earth chloride feed liquid to be impurity-removed, determining the types and contents of non-rare earth anions and cations in the feed liquid, and determining the type and dosage of a sustained-release agent; preparing the sustained-release agent and a carrier into an impurity removal agent; adding hydrochloric acid to the rare earth chloride feed liquid to be impurity-removed to adjust the pH value, and adding an impurity removal agent to remove impurities; after impurity removal, the feed liquid is separated into a solid-liquid state to obtain a rare earth chloride solution after impurity removal and an impurity removal residue; the impurity removal residue is stirred and washed with water to recover rare earth, and the obtained washed residue and washing water are filtered; the washed residue can be used as a carrier for recycling the preparation of an impurity removal agent after roasting and solidification. The present invention can remove Al in the rare earth chloride feed liquid. 3+ , Fe 3+ ,Th 4+ , U 6+ Non-rare earth cations and F ‑ 、SO4 2‑ Non-rare earth anions are removed simultaneously, and the loss of rare earth is small during the removal process.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for preparing an impurity-removing agent for rare earth chloride liquid and simultaneously removing non-rare earth anions and cations. Background Art

[0002] The impurity composition of rare earth concentrates from multiple sources is complex. 3+ , Fe 3+ ,Th 4+ , U 6+ Non-rare earth cations and F - 、SO4 2- Non-rare earth impurities are easily dissolved into the rare earth feed solution. When the traditional solution of adjusting the pH value by alkali or minerals is used to remove rare earth impurities, the pH value of the feed solution is too low and the impurities are not removed thoroughly, making it difficult to achieve a deep purification effect. Too high a pH value will cause a large amount of rare earth loss. When non-rare earth impurities enter the extraction tank, they will have a significant impact on the separation performance, process stability, and product quality of the extractant. In addition, a single impurity removal process often only has an impurity removal effect on a certain type of ion (anion or cation). The removal of non-rare earth anions and cations often requires multiple processes for processing, and the process flow is long. The loss of rare earths in the impurity removal process is large, and the cost of impurity removal is high. Summary of the invention

[0003] The purpose of the present invention is to develop a method for preparing a reagent for removing impurities from a rare earth chloride solution and for simultaneously removing non-rare earth anions and cations with a short process and low cost.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] A method for preparing a rare earth chloride liquid impurity removal agent and simultaneously removing non-rare earth anions and cations, comprising the following steps:

[0006] (1) Detect and analyze the rare earth chloride solution to be purified, determine the type and content of non-rare earth anions and cations in the solution, and use this to determine the type of sustained-release agent and calculate the required dosage of the sustained-release agent, wherein the non-rare earth cations include Al 3+ , Fe 3+ ,Th 4+ , U 6+ One or more of the non-rare earth anions include F - 、SO4 2- One or more of the above, the types of sustained-release agents include multi-component metal oxygen salts or carbonates composed of one or more of lanthanum, praseodymium, neodymium, calcium, magnesium and cerium;

[0007] (2) The slow-release agent and the carrier are mixed in a certain mass ratio to prepare a rare earth chloride liquid impurity removal agent, wherein the carrier includes one or more of kaolin, diatomaceous earth, and rare earth aluminum-containing impurity removal slag;

[0008] (3) The chlorinated rare earth liquid to be decontaminated is added with hydrochloric acid to adjust the pH value to 1.5-2.5, and an impurity removal agent is added to remove impurities;

[0009] (4) separating the impurity-removed feed liquid into solid and liquid to obtain an impurity-removed rare earth chloride solution and impurity-removed slag;

[0010] (5) removing impurities and residues, adding water, stirring and washing to recover rare earths, and filtering the resulting washed residues and washing water;

[0011] (6) After being calcined and solidified, the washed slag is used as a carrier for recycling to prepare the impurity removal agent.

[0012] Preferably, the actual molar amount of the sustained-release agent added is 1-10 times the molar amount of the non-rare earth cation.

[0013] Preferably, the ratio of the sustained-release agent doped into the rare earth chloride liquid impurity removal agent to the carrier is 1:1-1:8.

[0014] Preferably, the doping method of the impurity removal agent for preparing the rare earth chloride liquid includes one or more of the following methods: dry mixing (direct mixing of the sustained-release agent and the carrier powder), wet mixing with water followed by drying (adding water to the sustained-release agent and the carrier powder to form a slurry and then drying), and mixed firing (the carrier and the sustained-release agent precursor are mixed and then roasted).

[0015] Preferably, in step (3), the method of adding the impurity-removing agent to the chlorinated rare earth liquid to be impurity-removed is to stir and mix the solid and liquid, and the reaction temperature is room temperature.

[0016] Preferably, the solid-liquid separation method of the feed liquid after impurities removal includes one or both of plate and frame filter pressing and centrifugal separation.

[0017] Preferably, the weight-volume ratio of the impurity-removed slag to water for washing is 1:1-4, and the washing water is incorporated into the post-impurity-removed rare earth chlorination liquid.

[0018] Preferably, in step (6), the water-washed slag is calcined and solidified at a temperature of 500-1000° C., and the calcination time is 60-180 min. The calcined slag is evenly dry-mixed with the carrier material and can be used to prepare the impurity removal agent.

[0019] In view of the problem that non-rare earth anions and cations in the rare earth chloride feed solution are difficult to be removed synchronously and deeply, the present invention develops a method for preparing a rare earth chloride feed solution impurity removal agent and for synchronously removing non-rare earth anions and cations. 3+ , Fe 3+ ,Th 4+ , U 6+Non-rare earth cations and F - 、SO4 2- The non-rare earth anions are removed synchronously to achieve effective purification of rare earth liquid, less rare earth loss in the impurity removal process, and a rare earth comprehensive yield greater than 95%. Most of the waste residue after impurity removal can be recycled for the preparation of impurity removal agents, reducing the solid waste output of the impurity removal process. The process is simple, the impurity removal cost is low, it is economical and environmentally friendly, and has good prospects for industrial promotion. Specifically, the present invention has the following beneficial effects:

[0020] (1) The developed impurity removal agent can simultaneously remove F - 、Al 3+ , Fe 3+ ,Th 4+ , U 6+ The impurity ions are reduced to a low level, and the Al content in the rare earth liquid after impurity removal is 3+ <50mg / L,Fe 3+ <5mg / L、Th 4+ <0.1mg / L、U 6+ <0.1mg / L、F - <50mg / L, sulfate removal rate 20%-40%, which can effectively purify rare earth liquid;

[0021] (2) The rare earth loss during the impurity removal process is small, and the comprehensive rare earth yield is greater than 95%;

[0022] (3) The raw materials of the developed impurity removal agent are widely available and can be customized according to the requirements of liquid purification. Most of the impurity removal slag after disposal is returned as a carrier to prepare the impurity removal agent after roasting, resulting in less solid waste generation;

[0023] (4) The impurity removal process is simple and easy to operate, and can be operated using existing impurity removal process equipment with low investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0025] To further illustrate the present invention, the preparation of the rare earth chloride liquid impurity removal agent and the method for simultaneous removal of non-rare earth anions and cations provided by the present invention are described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] The analysis results of the rare earth chloride solution before impurity removal provided by a rare earth smelting enterprise are shown in Table 1.

[0028] Table 1 Analysis results of rare earth chloride solution before impurity removal in Example 1

[0029]

[0030] Accurately measure 50 ml of the rare earth chloride liquid in the above table. The selected sustained-release agent is lanthanum cerium carbonate. The theoretical amount of the sustained-release agent to be added is 0.26 g according to the molar amount of non-rare earth anions and cations. Accurately weigh 1.30 g of the sustained-release agent according to 5 times the theoretical amount, and dry-mix it with the carrier at a mass ratio of 1:8 to prepare the rare earth chloride liquid impurity removal agent;

[0031] 6 mol / L hydrochloric acid solution was added to the rare earth chloride solution to be removed to adjust the pH value of the solution from 2.54 to 1.58, and then the prepared impurity removal agent was added at one time. After stirring for 12 hours, the solution was separated into solid and liquid by vacuum filtration. The analysis results of the rare earth chloride solution after impurity removal are shown in Table 2.

[0032] Table 2 Analysis results of the rare earth chlorinated liquid after impurity removal in Example 1

[0033]

[0034] The impurity-removed residue after filtration was washed twice with water at a mass volume ratio of 1:1 and then filtered. The washing water was added to the chlorinated rare earth feed liquid after impurity removal. According to the amount of rare earth in the feed liquid, the comprehensive rare earth yield of the impurity removal process was 95.89%;

[0035] The washed slag was solidified by roasting at 500°C for 60 min and then used as a carrier to prepare the impurity removal agent. The impurity removal experiment was repeated under the above conditions. The analysis results of the rare earth liquid after impurity removal are shown in Table 3.

[0036] Table 3 Analysis results of rare earth liquid obtained after impurity removal when the washed slag after calcination and solidification in Example 1 is used as a carrier for impurity removal agent

[0037]

[0038] The analysis results of rare earth liquid after impurity removal show that the water-washed slag after calcination and solidification has a similar impurity removal effect when used as a carrier for the preparation of impurity removal agents.

[0039] Embodiment 2:

[0040] The analysis results of the rare earth chloride solution before impurity removal provided by a rare earth smelting enterprise are shown in Table 4.

[0041] Table 4 Analysis results of rare earth chloride solution before impurity removal in Example 2

[0042]

[0043] Accurately measure 50 ml of the rare earth chloride liquid in the table above. The selected sustained-release agent is cerium praseodymium oxide. The theoretical amount of the sustained-release agent to be added is 1.36 g according to the molar amount of non-rare earth anions and cations. Accurately weigh 5.44 g of the sustained-release agent according to 4 times the theoretical amount, and wet-mix it with the carrier at a mass ratio of 1:2 to prepare the rare earth chloride liquid impurity removal agent;

[0044] Because the pH value of the rare earth chloride solution to be impurity-removed has met the requirements, no further hydrochloric acid adjustment is required. The prepared impurity-removing agent is added at one time. After stirring for 12 hours, the solution is separated into solid and liquid by vacuum filtration. The analysis results of the rare earth chloride solution after impurity removal are shown in Table 5.

[0045] Table 5 Analysis results of the rare earth chlorinated liquid after impurity removal in Example 2

[0046]

[0047] The impurity-removed residue after filtration was washed with water three times at a mass volume ratio of 1:2 and then filtered. The washing water was added to the chlorinated rare earth feed liquid after impurity removal. According to the amount of rare earth in the feed liquid, the comprehensive rare earth yield of the impurity removal process was 99.89%;

[0048] The washed slag was solidified by roasting at 500℃ for 60min and then used as a carrier to prepare the impurity removal agent. The impurity removal experiment was repeated under the above conditions. The analysis results of the rare earth liquid after impurity removal are shown in Table 6.

[0049] Table 6 Analysis results of rare earth liquid obtained after impurity removal when the washed slag after calcination and solidification in Example 2 is used as a carrier for impurity removal agent

[0050]

[0051] The analysis results of rare earth liquid after impurity removal show that the water-washed slag after calcination and solidification has a similar impurity removal effect when used as a carrier for the preparation of impurity removal agents.

[0052] Embodiment 3:

[0053] The analysis results of the rare earth chloride solution before impurity removal provided by a rare earth smelting enterprise are shown in Table 7.

[0054] Table 7 Analysis results of rare earth chloride solution before impurity removal in Example 3

[0055]

[0056] Accurately measure 50 ml of the rare earth chloride liquid in the above table. The selected sustained-release agent is calcium cerium oxide. The theoretical amount of the sustained-release agent to be added is 0.67 g according to the molar amount of non-rare earth anions and cations. Accurately weigh 6.7 g of the sustained-release agent according to 10 times the theoretical amount, and wet-mix it with the carrier at a mass ratio of 1:1 to prepare the rare earth chloride liquid impurity removal agent;

[0057] 6 mol / L hydrochloric acid solution was added to the rare earth chloride solution to be removed to adjust the pH value of the solution from 3.45 to 1.68, and then the prepared impurity removal agent was added at one time. After stirring for 12 hours, the solution was separated into solid and liquid by vacuum filtration. The analysis results of the rare earth chloride solution after impurity removal are shown in Table 8.

[0058] Table 8 Analysis results of the rare earth chlorinated liquid after impurity removal in Example 3

[0059]

[0060] The impurity-removed residue after filtration is washed twice with water at a mass volume ratio of 1:2 and then filtered, and the washing water is added to the chlorinated rare earth feed liquid after impurity removal. According to the amount of rare earth in the feed liquid, the comprehensive rare earth yield of the impurity removal process is 98.99%;

[0061] The washed slag was calcined at 800°C for 60 min and solidified, and then used as a carrier to prepare the impurity removal agent. The impurity removal experiment was repeated under the above conditions. The analysis results of the rare earth liquid after impurity removal are shown in Table 9.

[0062] Table 9 Analysis results of the rare earth liquid obtained after impurity removal when the washed slag after calcination and solidification is used as a carrier for the impurity removal agent in Example 3

[0063]

[0064] The analysis results of rare earth liquid after impurity removal show that the water-washed slag after calcination and solidification has a similar impurity removal effect when used as a carrier for the preparation of impurity removal agents.

[0065] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent, characterized in that: The following steps are involved: (1) Detect and analyze the rare earth chloride solution to be purified, determine the types and contents of non-rare earth anions and cations in the solution, and calculate the dosage of the required sustained-release agent, wherein the non-rare earth cations include Al 3+ , Fe 3+ ,Th 4+ , U 6+ One or more of the non-rare earth anions include F - 、SO4 2- One or more of the following, the sustained-release agent includes one or more of lanthanum cerium carbonate, cerium praseodymium oxide, and calcium cerium oxide; (2) The slow-release agent and the carrier are mixed in a certain mass ratio to prepare a rare earth chloride liquid impurity removal agent, wherein the carrier includes one or more of kaolin, diatomaceous earth, and rare earth aluminum-containing impurity removal slag; (3) The chlorinated rare earth liquid to be decontaminated is added with hydrochloric acid to adjust the pH value to 1.5-2.5, and an impurity removal agent is added to remove impurities; (4) separating the impurity-removed feed liquid into solid and liquid to obtain an impurity-removed rare earth chloride solution and impurity-removed slag; (5) removing impurities and residues, adding water, stirring and washing to recover rare earths, and filtering the resulting washed residues and washing water; (6) After being calcined and solidified, the washed slag is used as a carrier for recycling to prepare the impurity removal agent.

2. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: The actual added molar amount of the sustained-release agent is 1-10 times the molar amount of the non-rare earth cation.

3. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: The mass ratio of the sustained-release agent doped into the rare earth chloride liquid impurity removal agent to the carrier is 1:1-1:

8.

4. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: The doping methods of the impurity removal agent for preparing the rare earth chloride liquid include one or more of the following methods: directly mixing the sustained-release agent with the carrier powder, adding water to the sustained-release agent and the carrier powder to form a slurry and then drying it, and mixing the carrier with the sustained-release agent precursor and then roasting it.

5. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: In step (3), the impurity removal agent is added to the rare earth chloride liquid to be impurity-removed by stirring and mixing the solid and liquid, and the reaction temperature is room temperature.

6. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: After impurities are removed, the solid-liquid separation method includes one or both of plate and frame filter pressing and centrifugal separation.

7. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: The impurity removal residue is added with water for washing in a mass volume ratio of 1:1-4, and the washing water is incorporated into the chlorinated rare earth liquid after impurity removal.

8. The method for simultaneously removing non-rare earth anions and cations in rare earth chloride solution by using a prepared impurity removal agent according to claim 1, characterized in that: In step (6), the water-washed slag is calcined and solidified at a temperature of 500-1000°C and a calcination time of 60-180 minutes. The calcined slag is dry-mixed with the carrier material and can be used to prepare an impurity removal agent.

Images